Iowa Corridor Management Pilot Project Overview Recommendations For A Corridor Management Program August 2004
Presentation Overview Project goals Pilot project selection process Analysis results Segment types 1, 2, and 3 Driveway and traffic signal inventory/density analysis Safety Land use Key findings Segment types and their typical issues Recommended program (summary) Retrofit studies on existing corridors with issues (mainly Segment 1 situations) Corridor management agreements on corridors where future corridor management issues are likely to arise (Segment 2 situations) Cooperative planning with local jurisdictions (Segment 3 situations)
Project Goals Identify typical Iowa corridor management issues and problems Develop safety and land use analysis techniques to be used on other corridors Develop a framework for corridor management in Iowa Involve several Iowa DOT offices plus Districts and metropolitan/regional planning organizations
Corridor Planning Pilot Project Selection Process Two pilot projects were selected by Iowa DOT management Both of the pilot corridors selected for detailed analysis ranked in the top ten in a previous study that identified the top priority candidates for corridor management in Iowa based on: Crash statistics Importance for commuting Likelihood of future access management issues
Key Commuting Routes In Iowa: 2004 Estimated Work Trips
Three Corridor Segment Types 1 1 Urban 2 Fringe 3 Rural 2 3
Segment 1 1 Urban Segments Urbanized Largely built out Predominately commercial land use Relatively well-managed in terms of commercial driveway density and medians Relatively high traffic signal density Low incidence of left-turning turning crashes; higher rates of right turn and (especially) rear-end end collisions at traffic signals Some opportunity for retrofit access management improvements
US 20 Urban Segment (1)
Segment 2 2 Fringe Segments Urbanizing (suburban and urban fringe) Largely undeveloped Considerable land development potential Likely use: mixture of commercial, industrial, and large lot residential Relatively well-managed in terms of commercial driveway density and medians at present A few traffic signals at major intersections or ramps Low incidence of left-turning turning crashes; higher rates of right turn and rear-end end collisions Considerable potential for future access management problems
US 20 Fringe Segment (2)
Rural Commuter Route Segments Segment 3 3 Rural, but within 30 minute commuter range Largely undeveloped Predominately agricultural land use Relatively well-managed in terms of commercial driveway density and medians No traffic signals Low incidence of left-turning turning crashes; low rates of right turn and rear-end end collisions Opportunities for spot access management problems at a few locations
US 20 Rural Segment (3)
Example Analysis Results: US 20 Corridor Near Dubuque Driveway locations and density Traffic signal location and density Safety: crashes frequency, type, and rate Land use: present and planned future
Driveway Density Analysis: US 20 Segment 1 Segment Length Driveway Count Driveways/ Mile 2.0 miles 9 4.5 (low) Segment 2 8.0 30 3.8 (low) Segment 3 15.8 5 0.3 (very low) Segment 2 has several instances of moderate density.
Traffic Signals And Driveways: Segment 1 And Portion Of Segment 2 US 20 In Dubuque High driveway density Signals <0.5 mile spacing
Segment 2 Driveways Areas of concern
Segment 3 Driveways Very well managed segment
Safety Analysis Crash frequency Focus on access-related crashes Left-turn, turn, right-turn, turn, and rear-end end collisions Access-related crash rates Access-related crash severity
Current Safety Analysis US 20: Access-Related Crashes Segment 1 Segment 2 Segment 3 Corridor Rear End 67 (35%) 27 (25%) 0 (0%) 94 (26%) Right Turn 18 (9%) 8 (7%) 1 (2%) 27 (7%) Left Turn 1 (1%) 3 (3%) 3 (5%) 7 (2%) All Access- Related Total Crashes 86 (44%) 38 (35%) 4 (6%) 128 (35%) 194 (100%) 108 (100%) 64 (100%) 366 (100%) Note: Columns do not total to bottom number. Difference is non-access crashes.
Access-Related Crash Rates US 20 Segment 1 Segment 2 Segment 3 Access- Related 4.2 (Moderate) 1.5 (Low) Near Zero Probable access-related crash rates per million vehicle-miles traveled. Includes right-turn, left-turn, and rear-end collisions.
Crash Hot Spots: Segment 1 Rear-End Collisions Predominate
Safety Analysis For US 20: Conclusions Overall Roughly 35% of all crashes in the corridor are access- related, but these are concentrated in the urban and suburban portions (Segments 1 and 2) Access-related crashes tend to be severe Driveway densities are generally not high on the route, but there are several concentrations of commercial driveways that could be consolidated Segment 1 Has significant numbers of rear- end collisions and right turn crashes This is consistent with a multilane divided corridor with a high public road intersection density and high traffic signal density Segment 2 Has a less significant access- related safety problem than Segment 1 There are three problem sub- segments Some safety problems are associated with public road intersections rather than with driveways Segment 3 Safety problems are generally not access-related (crashes are run off the road, weather-related, related, animal crashes, etc.)
Land Use Analysis Analysis process employed current and projected future land development in GIS format Segment 1 Largely commercial Essentially built-out; little potential for further development except if re-developed Segment 2 Mixture of commercial, industrial, and agriculture Considerable potential for new commercial and industrial development with associated demand for driveways Segment 3 Largely agricultural except in and around cities Limited development at the edges of small cities
Segment 1: Largely Commercial And Mainly Built-Out
Segment 2: Mixed Land Use With Much Room For More Development Classic strip development
Segment 3: Mainly Agricultural With Mixed Use Near Cities
Future Land Use Analysis: US 20 Segment 1 will continue to exist as a commercial strip with some changes in individual parcels and businesses Segment 2 will likely continue to develop as a commercial/industrial strip (eastern half) and large lot residential (western half) This segment has (by far) the most potential for future land development Segment 3 will likely remain largely agricultural except in and near Peosta, Epworth, Farley, and Dyersville (small cities along the corridor)
Segment 2: Planned Industrial Development (Yellow)
Segment 2: Planned Development At The Dubuque Fringe (Yellow and Red)
Large Portions Of Segment 2 Are Planned As Low Density Residential Commercial uses (red) are clustered positive feature
Segment 3: Limited New Development Planned
Corridor Management Issues By Segment 1 Segment Type High density of public road intersections and median breaks High density of traffic signals Close spacing leads to a decline in mean travel speed, reduction in LOS, and an increase in rear end collision rates Lack of dedicated turning lanes at major intersections Discontinuous frontage road system Frontage road system too close to the mainline A handful of direct driveway accesses could be closed or consolidated
Corridor Management Issues By Segment 2 Segment Type Several areas with direct driveway accesses that could be closed or consolidated Areas of high crash rates that are usually related to land development and access decisions Discontinuous frontage road system Large potential for future access management issues as land develops Especially important in areas slated for commercial and industrial development
Corridor Management Issues By Segment 3 Segment Type Spot safety issues associated with individual developments Examples: Existing and potential commercial development near Farley and Epworth located around at-grade intersections Large, new BMX (cycling) facility located in a rural area
Overall Corridor Management Goals Reduce at-grade public road intersection density (full intersections), full median break density, and traffic signal density along Segment 1 Reduce direct driveway accesses where possible through driveway sharing and alternative access way development along Segment 2 Develop a complete frontage and backage road system where appropriate with a substantial separation from the mainline Improve land use planning along Segments 2 and 3 so that new commercial developments are clustered around existing and planned interchanges Clear commercial driveways a reasonable distance away from interchanges and major intersections
Ideal Corridor Configuration Segment 1 Urban expressway with high level of access control (or a freeway) 45-55 55 mph mean travel speed Traffic signals spaced at least ½ mile apart No direct driveway accesses Full frontage road system with accesses to mainline at interchanges at least ½ miles apart (ideally 1 mile apart) Segments 2 and 3 Suburban/rural expressway with high level of access control 55-65 mph mean travel speed Full median break spacing >1 mile (no traffic signals) Driveway spacing >0.25 miles (right-in in right out only, where possible ) Backage road system with accesses to mainline separated at least 1 mile
Suggested Iowa Corridor Management Program Framework Segment 1 Develop retrofit access management plans Segment 2 Develop corridor management 28E agreements New Iowa US 6 agreement as a model (District 4, Iowa DOT) NCHRP Synthesis as a tool Segment 3 Cooperative planning with local land use planning jurisdictions Spot corridor safety improvements Overall Improved inventories of driveway permit locations, access priority classification levels, and access rights obtained Automated access permitting system?
Suggested Items To Be Addressed In A Retrofit Access Management Study Segment 1 Situations Inventory: driveways, medians, Safety analysis: crash rates, locations, and types Present and future land use Traffic signal location and spacing Improved traffic control systems Dedicated turning lanes Frontage or backage road system and internal circulation in adjacent developments Consolidation and clearance of commercial driveways
Suggested Items Recommended To Be Included In A Corridor Management Intergovernmental Agreement Segment 2 Situations Public road interchanges and intersections Traffic signal locations Medians and median break locations Driveway locations and directions (e.g. right-in, in, right-out) Dedicated turning lane locations Alternative access ways (e.g. development of frontage and backage road systems) Generalized land use planning
Items That Could Be Pursued In Rural Parts Of Corridors Segment 3 Situations Some communities along key commuting corridors have no comprehensive land use plans or badly outdated plans Encourage them to develop and update plans Cooperatively review new development proposals for potential access and safety issues, especially those that involve commercial and industrial development Conduct spot safety and access analyses at current and potential problem locations
Expected Benefits Of A Corridor Management Program Preservation of the Iowa DOT s s multi-million million dollar investments in major corridors Maintain mean travel speed and LOS, especially on Segment 1s Lower rear-end end collision rates (mainly on Segment 1s) Lower right and left turning crash rates (mainly on Segment 2s) Preservation of Segment 3s, which are generally well- managed and safe now Maintenance of business environment on Segment 1s, which might otherwise begin to suffer due to higher travel times and greater congestion
Current Program Status Several Iowa DOT offices (Development, Location, Safety, Planning) are involved Each Iowa DOT District (1 through 6) is identifying a corridor for which an Intergovernmental Corridor Management Agreement will be developed between Iowa DOT and local governments Retrofit access management studies are being programmed as needed MPOs and Regional Planning Affiliations being included as partners
For More Information Contact: David Plazak Associate Director for Policy Center for Transportation Research and Education Iowa State University Research Park Phone: 515-296 296-0814 dplazak@iastate.edu